Supportive wick structure of planar heat pipe

ABSTRACT

A supportive wick structure of a planar heat pipe is provided having two panels and a supportive body with a plurality of low guides and through holes. The supportive body provides flow channels for a working fluid of the heat pipe in two directions. The flow guides formed by flow guide projections enhance structural strength and provide channels for the working fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application is a Continuation-in-Part of application Ser. No. 09/576,347, filed May 22, 2000, and entitled SUPPORTIVE WICK STRUCTURE OF PLANAR HEAT PIPE.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a supportive wick structure of a planar heat pipe. More particularly, the present invention is directed to a panel structure that provides both supportive and wick functions.

[0004] 2. Prior Art

[0005] Conventional heat conducting devices generally comprise heat pipes and heat plates, both of which have upper and lower panels and a wick (capillary) structure. By the capillary attraction of the wick structure, the vapor of the working fluid flows to a cool site and exchanges heat to condense to a liquid state. The wick structures are generally composed of a screen mesh or a sintered structure to provide capillary attraction. For the wick structures composed of screen mesh, the wick structures have no supportive function for the panel and the flow within the screen mesh may be blocked by the panel. As shown in FIG. 13, the conduction panel 4 has groove-shaped projections to guide fluid. However, this kind of conduction panel 4 provides one-dimensional guiding, only along a single direction, and not along transverse directions. Moreover, two conduction panels with the groove-shaped projections normal to each other, are proposed to provide two-dimensional guiding, along two directions. However, for each individual conduction panel, only one-dimensional guiding, along a single direction is provided, and the overall structure is bulky.

SUMMARY OF THE INVENTION

[0006] It is the objection of the present invention to provide a supportive wick structure of a planar heat pipe, whereby the planar heat pipe has better structural strength and heat conducting ability.

[0007] To achieve the above objects, the present invention provides a supportive wick structure of a planar heat pipe having two panels. The supportive wick structure comprises a supportive body with a plurality of flow guides and through holes to provide two-dimensional guiding functions for a working fluid in the planar heat pipe. The flow guides enhance structural strength of the supportive body and provide channels for the working fluid.

[0008] When the flow guides are formed by flow guide projections, stamped from a thin plate in a punch press, the porosity of the supportive body is increased and the cross-section of the material surrounding the flow channels is reduced. Therefore, the hydraulic resistance thereof is reduced. As flow channels are formed between the flow guide projections and through openings formed by the projections, increased flow channels are formed, providing the increased porosity.

[0009] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a perspective view of a supportive body of the present invention;

[0011]FIG. 2 is a perspective view of a supportive body of the present invention formed from a thin plate;

[0012]FIG. 3 is a perspective view of a supportive body of the present invention formed from a thin plate with strip-shaped projections;

[0013]FIG. 4 is a perspective view of a supportive body of the present invention formed from a thin plate with randomly positioned projections;

[0014]FIG. 5 is a cross-sectional view showing the supportive body of FIG. 1 assembled in a heat plate;

[0015]FIG. 6 is a cross-sectional view showing the supportive body of FIG. 1 assembled in a heat plate with additional wick structures;

[0016]FIG. 7 is a cross-sectional view showing a pair of supportive bodies of FIG. 1 assembled in a heat plate;

[0017]FIG. 8 is a cross-sectional view showing a pair of supportive bodies of FIG. 1 assembled in a heat plate with additional wick structures;

[0018]FIG. 9 is a cross-sectional view showing the supportive body of FIG. 2 assembly in a heat plate;

[0019]FIG. 10 is a cross-sectional view showing the supportive body of FIG. 2 assembled in a heat plate;

[0020]FIG. 11 is a cross-sectional view showing a pair of the supportive bodies of FIG. 2 assembled in offset relationship in a heat plate;

[0021]FIG. 12 is a cross-sectional view showing a pair of the supportive bodies of FIG. 2 assembled in offset relationship in a heat plate with additional wick structures; and

[0022]FIG. 13 shows a plan view of a prior art heat plate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023] With reference now to FIGS. 1 to 12, the present invention is intended to provide a supportive wick structure of a planar heat pipe. The planar heat pipe comprises at least one supportive body 1 formed from a thin plate with a plurality of flow guides 10 thereon. The thin plate may be formed of solid material or of wick material. The supportive body 1 is sealed between a pair of plates with a working fluid contained therein. As shown in FIG. 1, the flow guides 10 are grooves 11 formed on the supportive body 1 by pressing or extrusion and in array arrangement. As shown in FIG. 2, the flow guide projections 10 are in an array arrangement. The supportive body 1 is formed from a thin plate, having a thickness in the range of 0.05-1.0 mm, in which a plurality of flow guide projections 10′ are formed, each forming an opening 11. The flow guide projections 10′ are formed by stamping with a punch press. Thus, the opening 11 is pierced by a press and the material displaced from the hole is formed into the flow guide projection.

[0024] The flow guide projections being punched from a planar surface thereby form additional flow channels through the openings 11. The openings 11 have a trapezoidal contour and may have an arcuate contour, such as semicircular contour where greater resistance to compression is required. Thus, the leading edge of each flow guide projection 10′, the material around each opening 11, is of small cross-section, within the range of 0.05-1.0 mm, to minimize hydraulic resistance to flow of the working fluid. The matrix formed by the flow guide projections 10′ creates a two-dimensional flow space. The flow guide projections 10′ provide a plurality of longitudinal fluid flow channels A, a plurality of transverse fluid flow channels B between adjacent projections 10′, and a plurality of transverse fluid flow channels C through the openings 11. By that arrangement, there is a greater flow space, increased porosity, reduced hydraulic resistance, and increased heat transfer efficiency.

[0025] As shown in FIG. 3, the flow guides 10 are formed by a combination of the projections 14, like the projections 10′ shown in FIG. 2, and strip-shaped projections 15 to provide communication between two rows of projections 14.

[0026] As shown in FIG. 4, the projections 16, 17 and 18 are in random arrangement. In the embodiments shown in FIGS. 1 to 4, a plurality of lengthwise through holes 19 are formed on the supportive body 1 to define flow guide slots that provide two-dimensional fluid guiding. The working fluid of the heat pipe can flow in longitudinal and transverse directions. The supportive body 1 with flow guides 10 and lengthwise through holes 19 together provide supportive function and guide the working fluid flowing in two directions. The through holes 19 provide main channels through which the working fluid flows back and the flow guides 10 provide main channels through which vapor flows back. However, the function of the through holes 19 and the flow guides 10 are not limited to the above-mentioned usage.

[0027] As shown in FIGS. 7, 8, 11, and 112, a plurality of supportive bodies 1, 1′ can be stacked for use of in back-to-back or offset stack arrangement. As shown in FIG. 6, a pair of additional wick structures 3 on each side of a supportive body 1 are respectively sandwiched between the supportive body and the two panels 2 of the planar heat pipe. Each additional wick structure 3 may be formed by a screen mesh or other capillary structure. As shown in FIG. 7, two supportive bodies 1 are stacked in a back-to-back arrangement. FIG. 8 shows an additional wick structure 3 added between each supportive body 1 and a respective panel 2 of the heat plate of FIG. 7. FIG. 9 shows a planar heat pipe with the supportive body of FIG. 2 sandwiched between the two panels 2 and 2′ having upper flow passages B and lower flow passages C. The supportive body 1 is sealed within an interior space defined between the panels 2, 2′ with the working fluid disposed in the plurality of flow channels. FIG. 10 shows a planar heat pipe with the supportive body 1 of FIG. 2 and two additional wick structures 3 sandwiched between the supportive body 1 and the two panels 2 and 2′. FIG. 11 shows a planar heat pipe with two of the supportive bodies 1, 1′ of FIG. 2 stacked in a shifted manner to be in offset relationship to form interior and exterior flow channels B′, C′. The exterior flow channels C′ are larger than the interior flow channels B′. FIG. 12 shows an additional wick structure 3 added between each supportive body 1, 1′ and a respective panel 2, 2′ of the heat plate of FIG. 11.

[0028] To sum up, the present invention uses supportive bodies in a conventional planar heat pipe to provide wick and supportive functions. the flow guides 10 and the through holes 19 provide two-dimensional guiding functions for the working fluid, providing flow channels in each of two orthogonal directions. The flow guides 10 can be arranged in random style and can have through holes on top thereof to provide design flexibility. The heat dissipation effect is enhanced.

[0029] The supportive body can be efficiently fabricated from a thin plate, forming the plurality of flow guide projections with a punch press. The supportive body is thereby light weight and capable of providing both structural support and function as a wick structure to provide flow channels for the working fluid. The supportive body itself may be formed of wick material. The heat plate using one or more of the supportive bodies may also include a pair of additional wick structures to provide further flow channels for the working fluid.

[0030] Although the present invention has been described with reference tot he preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur o those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims. 

What is being claimed is:
 1. A supportive wick structure of a planar heat pipe, comprising at least a supportive body being a thin plate formed with a plurality of flow guide projections thereon, said flow guide projections each defining a pierced hole by pressing; said flow guide projections and said flat plate being correspondingly supported to an upper panel and a lower panel of the planar heat pipe, so that the supportive body is disposed between the upper panel and the lower panel to form a two dimensional flow space; whereby a working fluid is able to flow omni-directionally within the planar heat pipe.
 2. The supportive wick structure of a planar heat pipe as in claim 1, wherein said flat palate of said supportive body is formed with a plurality of flow guide slots.
 3. The supportive wick structure of planar heat pipe as in claim 2, wherein said flow guide slots are correspondingly positioned beside said flow guide projections.
 4. The supportive wick structure of a planar heat pipe as in claim 1, wherein said flow guide projections of said supportive body are arranged in a matrix form.
 5. The supportive wick structure of a planar heat pipe as in claim 1, wherein said supportive body has an upper end and a lower end each disposed with a wick layer.
 6. The supportive wick structure of a planar heat pipe as in claim 1, wherein said guide projections each have a trapezoidal shape or a semicircular shape for compression.
 7. The supportive wick structure of planar heat pipe as in claim 1, wherein said guide projections are irregular or differ in size, respectively.
 8. The supportive wick structure of a planar heat pipe as in claim 1, wherein said supportive body is made of wick material. 